Depression, quality of life and cortisol: a cross-sectional study of caregivers of patients with Alzheimer’s disease

Background: Stress can impact human health in multiple ways. Among the related mechanisms are the hormonal systems of the hypothalamic–pituitary–adrenal axis, which produces cortisol. Current research aims to evaluate the relationship between the daily variation of salivary cortisol dosages and the level of stress in caregivers of patients with Alzheimer's disease (AD). Methods: A sociodemographic questionnaire was applied to 25 caregivers, as well as the 36 Item Short-Form Health Survey and Beck’s Depression Inventory. In the 25 patients of the caregivers, the Instrumental Activities of Daily Living of the patient and Clinical Dementia Rating were assessed. Saliva samples were collected to assess the cortisol level of the caregivers three times over one day for each caregiver, (morning, afternoon and evening) to investigate the correlation of the aforementioned questionnaires with the age and degree of kinship among caregivers of elderly patients to investigate the correlation with the results of the previously described tests, and the age and degree of relatedness of caregivers and elderly patients. Results: There was a significant positive correlation between daily cortisol levels and increasing caregiver age. However, the daily dosage of salivary cortisol was not significantly associated with the stress level of the caregivers of patients with AD, suggesting that this is not a good neuroendocrine marker of response to mood disorders. This fact can be related to intrinsic and extrinsic factors to the caregiver. Conclusions: Compared with previous studies that correlate cortisol and stress in humans, our findings suggest that the stress mechanism may be more complex and depend on more factors than the levels of this hormone. Thus, further work is required to delineate possible cortisol modulators, as well as the type of stress that target this population and their ability to adapt and face adversity in their work.